The bachelor thesis describes in detail structural intervals with regard to building insulation and without thermal insulation. The introduction of the thesis contains the basic terminology of safety structural intervals, fire hazard area, fire open areas, methods of thermal insulation systems and insulation materials. At the beginning of the work is given a general description of the calculation of structural intervals and their solutions. The main objective was to calculate and compare the spacing relationships of the new building without external surface treatment and with a surface treatment - via a flammable contact insulation system made of polystyrene for the same new building. At the end of the thesis, the difference between the size of the fire area and the length of the structural intervals is indicated. The result of the work is that when the polystyrene is insulated with the new building, greater spacing distances have been established and it has been confirmed that the flammable surface treatment of the perimeter wall should be taken into account in the PBS solution in determining the spacing distances.